A Composite Structure Multi-Parameter Sensor Based on an Embedded Fiber Grating

A composite structure multi-parameter sensor based on an embedded polarization maintaining fiber grating (PMFG) has been studied theoretically and experimentally. A fiber Bragg grating (FBG, for comparison with the PMFG) and a PMFG are embedded in glass fiber reinforced polymer (GFRP) laminates in the experiment. The temperature and stress response characteristics of the fiber gratings embedded in corresponding GFRP are studied. The temperature sensitivity of the FBG improves from 10.64pm/℃ to 21.66pm/℃. The temperature sensitivity of the PMFG improves from 10.22m/℃ to15.7pm/℃ (x-axis) and from 9.56 pm/℃ to15.1 pm/℃ (y-axis). The peak wavelengths in the reflection spectra of the two gratings all shift linearly with the temperature and/or the stress of GFRP. The two temperature-wavelength sensitivities and the two stress-wavelength sensitivities of the PMFG are all different with each other. The temperature and the stress of the GFRP can be calculated according to the two peak wavelength (in x-axis and in y-axis) shifts of a PMFG. Therefore, one PMFG is component for monitoring the temperature and the stress of a composite structure simultaneously according to the experimental results.